1. Field of the Invention
The present invention relates generally to wireless systems, and more specifically, but not exclusively, to a method and apparatus relating to transmission and reception of data streams in digital video broadcast systems.
2. Description of the Related Art
A wireless system, such as a digital video broadcasting system, may transmit data in the form of a sequence of frames arranged in a frame structure. A digital video broadcasting system generally complies with digital video broadcasting standard, and the digital broadcasting standard may include, for example, Digital Video Broadcasting (DVB), Advanced Televisions Systems Committee (ATSC), Integrated Services Digital Broadcasting (ISDB) or Digital Multimedia Broadcasting (DMB). Each frame typically comprises a preamble section and a data section, the preamble section and the data section being time-multiplexed. The data section may include data that is arranged in the form of a number of data streams that may be referred to as physical layer pipes (PLP). A physical layer pipe may carry, for example, a service such as a video channel provided to a user. Data or data streams from the frames may be received using signaling information. The signaling may be referred to as physical layer signaling, or Layer 1 (L1) signaling. The signaling may indicate a modulation or coding scheme to be used for receiving data, and it may indicate sections of a data field to be decoded, or indicate information needed for data reception such as the location of a data stream within the data section.
Referring to the Digital Video Broadcasting (DVB) standard, Digital Video Broadcast standard frame structures may provide physical slots within the DVB physical frame structure, which are reserved for future use. For example, Digital Video Broadcasting Terrestrial 2″ generation (DVB-T2), the terrestrial broadcasting standard, has a superframe structure including multiple frames, and includes slots that do not carry DVB-T2 signals, in the superframe or each frame. It is referred to as Future Extension Frame (FEF) slots. In other words, FEF slots may be provided in addition to the parts of the frame structure which are for transmission of signals intended for reception by conventional fixed Digital Video Broadcast receivers.
Referring to Digital Video Broadcasting Next Generation Handheld (DVB-NGH) for reception of mobile broadcasting, which is currently being established, digital video broadcasting systems may provide for the transmission of signals specifically intended for reception by mobile broadcasting receivers and hand held devices. Such signals may be, for example, of lower bandwidth and have more robust modulation and coding than signals intended for reception by fixed receivers.
There have been proposals to use the additional physical slots, such as the FEF slots, for the transmission of signals intended for reception by handheld receivers. Typically, the additional physical slot includes signaling information for reception of data transmitted on the physical slots or frames.
However, such a scheme, in which the signaling information is arranged in each of the physical slots, may suffer from limited capacity, due to short physical slot duration and high signaling overhead. Furthermore, such a scheme may be limited in terms of achievable statistical multiplexing gain, due to the limited capacity that may be achieved.